A brand new type of coronavirus vaccine has just been tested in rhesus monkeys (New England Journal of Medicine, online July 28, 2020). Results published in The New England Journal of Medicine show that the messenger RNA (mRNA) vaccine from Moderna induced a strong antibody response to SARS-CoV-2.
How Effective Was the mRNA Vaccine for the Monkeys?
Vaccinated monkeys also responded with increased type 1 helper T cells in their blood. Even better, the scientists challenged the monkeys with a solution of the coronavirus in their noses or their windpipes. They could not find evidence that the virus replicated in those regions. Moreover, the vaccinated animals did not become ill. The vaccine prevented the virus from binding to ACE2 receptors in the lungs. The unvaccinated animals exposed to the virus developed severe inflammation in their alveoli and small airways, just as many human COVID-19 patients do.
The scientists say these data complement the information garnered from a phase 1 trial of the vaccine in humans. Moderna has also completed phase 2 trials and is now ready for phase 3 trials. The company will be recruiting 30,000 volunteers around the US to test this mRNA vaccine. Success in rhesus monkeys gives us all hope that the vaccine will be effective. However, we won’t know for sure until humans have used it.
Other Vaccines for COVID-19 Are on the Way:
Moderna’s vaccine is not the only one on the fast track to development. Scientists are currently studying more than 150 vaccines. In fact, one from the University of Oxford/AstraZeneca has already entered phase 3 trials in Brazil. Animal studies on a killed virus vaccine from Sinovac Biotech were promising, and it is also in phase 3 trials in Brazil. Pfizer, like Moderna, is developing a vaccine using novel mRNA technology. We hope that at least one, and preferably several, of these candidates proves safe and effective so that we can finally overcome the pandemic. In the meantime, we all need to continue to wash our hands, wear our face masks and maintain six to ten feet of distance between us whenever we are not at home with our families.